The present invention relates to a retroreflector for reflecting electromagnetic rays, which is suitable for destroying, by reflection or absorption, electromagnetic radiation, which could lead to a lasting influencing on magnetic or other data carriers, particularly as a protective device for data memories.
In modern computing and data processing installations, memories are used for storing information. These memories are, for example, constructed in central processing units of data processing installations or used as external memories. Use is generally made of the laws of electromagnetism for storing information. Thus, magnetic core, tape, bubble and drum memories are known.
In such memories, and, in particular, in read-only memories, information is frequently stored which is only present therein and to which no other access is possible. It has therefore proved to be a problem to protect such memories against damage and hence the destruction of the stored information material. It has admittedly already been proposed to arrange such memories in building rooms in which mechanical influencing of the memories is largely excluded. However, even in these rooms, it is not possible to ensure a completely effective protection against detrimental influences or destruction of the memories by the action of electromagnetic radiation.
Thus, if a velocity-modulated tube of corresponding power level is operated in the vicinity of a data memory, the electromagnetic radiation from the tube can detrimentally influence and/or destroy the data material, so that on again obtaining access to the data, it is established that the data memories only contain inadequate or no information.